Carl luckow



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CARL LUOKOTV, OF COLOGNE-DEUTZ, GERMANY.

SPECIFICATION forming part of Letters Patent No. 626,331, dated June 6, 1899-.

Application filed December 31, 1897.

T0 aZZ whom it ntay concern:

Be it known that I, CARL LU OKOW, a subject of the King of Prussia, German Emperor, residing at Cologne-Deutz, Germany, have i11- vented certain new and useful Improvements in Processes of Producing Neutral Ghromate of Lead by Means of Electrolysis, of which the following is a specification.

The invention has been patented in England, No. 14,801, dated August 6, 1895.

The object of this invention is to produce neutral chroinate of lead by means of electrolysis.

It consists, essentially, in the use as electrolyte of a salt of chloric acid with sodium, potassium, or ammonium in mixture with a salt of chromic acid with sodium, potassium, or ammonium in aqueous solution in connection with anodes of lead. The mixture should be about eighty per cent. of one of the salts named above of chloric acid and about twenty per cent. of one of the salts named above of chromic acid, and the aqueous solution should contain from 0.3 to three per ecnt. of the mixture, the quantities of salt always calculated free from water. This solution serves as electrolyte. The electrodes are of lead. Under the influence of the electric current the lead of the anode is dissolved by the chloric acid of the one salt forming chlorate of lead, which dissolves and is directly precipitated by the chromic acid of the other salt, as chromate of lead. At the same time water is decomposed, the oxygen of which enters into the chromate of lead, while the hydrogen escapes. V The chromic acid thus consumed must be continuously added afresh to the electrolyte. By the use of such two salts in The process goes on continu- Serial No. 665,211. (No specimens.)

ously with the same electrolyte, as the chloric acid is not decomposed by the electric current and as the chromic acid and water consumed in the process are always added as they are consumed. The electrolyte being kept neutral, neutral chromate of lead is obtained.

Example: A diluted solution one and onehalf per cent. strong of a mixture of eighty parts, by weight, of chlorate of sodium and twenty parts, by weight, of chromate of sodium forms the electrolyte. The anode consists of soft lead and the cathode of hard lead, an alloy of lead and antimony containing five to ten per cent. of the latter. The electrolyte is neutral. The tension of the current is 1.8 volts. The density of the same is fifty amperes. The density of the same is 0.5 amperes per square decimeter of anode-surface. The electrolyte has to be kept neutral during the electrolysis, and water and chromic acid have continuously to be added.

What I claim is The herein-described process of producing neutral chromate of lead by means of electrolysis consisting in using an anode of lead in connection with an aqueous solution as electrolyte containing from three-tenths to three per cent. of the sodium, potassium or ammonium salts of chloric acid in mixture with the sodium, potassium or ammonium salts of chromic acid, passing electric current through the said solution and maintaining the bath constant by the continuous addition of water and chromic acid, substantially as described.

In witness whereof I have hereunto set my hand in presence of two witnesses.

CARL LUCKOV.

Witnesses:

O'r'ro STnncKnn, WILLIAM M. MADDEN. 

